It is a predictable trend that future telecommunications will have collectively integrated functions due to the amazingly rapid development of semiconductors, computers, and data transmission technologies. Therefore, instead of signal information which is used during the communication network exchange period being transmitted together with the user's information, as is now conventional, it will be an imperative demand that common channel signalling be introduced for transmitting the signal information through a common channel separate from the transmission line for the user's information. The development of a signalling transfer point for exclusively perfoming the transmission of such signal information is an important task which will bring a new era in automated information.